I study physics, not computer science, so I apologize if I mangle anything.

My theory is that Ennesby is built around a modular approach, with a high level process managing all the modules into something like an OS kernel. So, need to migrate to new hardware? No problem, write the hardware routines and integrate this new module. Or, someone dumped a bunch of memories and personality structure? Well, just boot it up as a module, it will be just fine.

Normally, that makes Chinook the same person as Tagii, just one who was revived from gestalt in an very complicated way. But while Tagii was running as a subroutine of the Ennesby master structure, Ennesby edited her significantly. So I think that Chinook is related to, but not the same person as Tagii.

In other words, Chinook is a result of Tagii and Ennesby interacting. In a weird way, that makes her kind of like their child.